Six Japanese children with rapidly progressive Henoch-Schönlein purpura nephritis (HSPN) received multiple drug therapy combined with plasmapheresis (PP). After five courses of PP, multiple drug therapy, including methylprednisolone and urokinase pulse therapy, oral prednisolone, cyclophophamide, dipyridamole, and warfarin was given. At presentation, urine protein excretion and histological indices of the mean activity and chronicity were 245+/-101 mg/m(2) per hour, 6.6+/-1.2, and 1.5+/-1.3, respectively. After 6 months of therapy, urinary protein excretion had decreased significantly ( P<0.001). The activity index decreased significantly at the second renal biopsy performed at a mean interval of 4.3 months after the first (2.8+/-1.4, P<0.05), while the chronicity index did not change. At the most recent observation, all showed clinical improvement. Two patients had normal urine, three had proteinuria of <20 mg/m(2) per hour, one had proteinuria of >20 mg/m(2) per hour, and none had renal insufficiency. Although this case series is without controls, our treatment protocol may be of benefit to children with rapidly progressive HSPN.